The Trinity is the Christian doctrine that there is one God who is known as Father, Son, and Holy Spirit. Mainstream Catholic, Eastern Orthodox, Oriental Orthodox, Anglican, Lutheran, Reformed, Methodist, Baptist, and many other churches are Trinitarian.
One God, three persons
Trinitarian Christianity does not teach belief in three gods. It teaches one God in three distinct persons. The Father is not the Son, the Son is not the Holy Spirit, and the Holy Spirit is not the Father; yet Christians who accept the doctrine hold that each is fully divine and that God is one.
Biblical background
The word “Trinity” does not appear in the Bible. The doctrine developed as early Christians interpreted scripture about the one God of Israel together with New Testament claims about Jesus Christ and the Holy Spirit. Baptism “in the name of the Father and of the Son and of the Holy Spirit” became especially important in later doctrinal language.
Nicaea and Constantinople
The fourth century was decisive. The Council of Nicaea in 325 rejected the claim that the Son was a created being and used the term homoousios, usually translated “of one substance” or “of one essence,” to describe the Son’s relation to the Father. The Council of Constantinople in 381 helped establish the form of the Nicene Creed used widely in Christian worship.
What the doctrine is trying to express
The doctrine holds together several claims: God is one; the Father is God; the Son is God; the Holy Spirit is God; and the three are not simply different names for one person. Classical Trinitarian theology uses terms such as “one essence” and “three persons” to express this distinction without dividing God into separate beings.
Differences among Christian traditions
Western and Eastern Christianity share the basic Trinitarian doctrine but have disagreed over the wording of the creed concerning the procession of the Holy Spirit. The Western addition commonly called the filioque became one issue in the long division between Eastern and Western churches.
Some groups that identify as Christian are nontrinitarian. Their interpretations of God, Jesus, and the Holy Spirit differ from the doctrine defined by the ancient ecumenical creeds.
The Trinity in worship
Trinitarian language appears in baptism, creeds, hymns, blessings, and liturgical prayer. Christians may pray to the Father through the Son in the Holy Spirit, while also addressing Christ or the Holy Spirit directly in many traditions.
The Trinity is therefore not a claim that Christians worship several gods. It is the classical Christian way of describing how one God is understood in relation to the Father, the Son, and the Holy Spirit.
